Isolation and Characterization of Avian Coronavirus from Diagnostic Cases of Selected Bird Species in Malaysia

Infectious bronchitis virus (IBV) in chicken (Gallus gallus) is the most common and well-studied Avian coronavirus (ACoV) in avian species. The study aims to molecularly characterize ACoV isolate of selected bird species other than chicken obtained from the archived samples of field diagnostic cases in the Northern Zone Veterinary Laboratory (MVZU), Malaysia. Twelve archived virus isolates from 2013 to 2019 were amplified using selected primers on the 3' UTR gene and S1 gene for oligonucleotide sequencing. These sequences were then molecularly characterized and compared with common IBV strains in chicken to determine the genetic diversity of the virus among selected avian species. Subsequent analyses of the nucleotides amplified on 3' UTR conserved region of 12 selected ACoVs isolates originating from peacocks (Pavo cristatus), turkey (Meleagris), jungle fowl (Gallus gallus spadiceous), guinea fowl (Meleagris gallopavo domesticus), goose (Anser anser domesticus), love bird (Agapornis), macaw (Ara macao), and bird (species unidentified) are classified as belonging to the gammacoronavirus (Gamma-CoV) genus and have a high degree of homology. The S1 complete gene sequence analyses of guinea fowl and jungle fowl showed that both ACoV isolates are Gamma-CoV and under genotype I and GI-13 lineages. Both are identified as having a high similarity of 98% and 99%, respectively, with IBV vaccine strain 4/91 (AF093793). Due attention should be given to ACoVs strains, especially the IBV vaccine strains detected in other bird species, because there is a high probability that other bird species could be the source of pathogenic ACoV infection in general and IBV infection in chickens, as reported in other countries.